1. Field of the Invention
The present invention relates to a cylinder block for a water-cooled internal combustion engine. More specifically, the present invention relates to a cylinder block in which a rigidity of a top deck is ensured by forming an external flange at the top deck of the cylinder block.
2. Background Information
Japanese Patent Application Laid-Open No. 2002-161803 describes a conventional cylinder block for a water-cooled internal combustion engine that includes a cylinder wall in which a plurality of pistons are disposed such that the pistons can reciprocate within the cylinder walls, and a jacket sidewall disposed in the periphery of the cylinder wall. In the conventional cylinder block disclosed in the above mentioned reference, a water jacket is formed between the cylinder wall and the jacket sidewall so that the heat is transferred from the cylinder wall to the coolant in the water jacket and the cylinder wall is cooled by the coolant circulating through the water jacket. In the conventional cylinder block, a cylinder head is fixedly coupled to the cylinder block by a plurality of head bolts with a head gasket disposed on a top deck of the cylinder block, and the water jacket of the cylinder block has an open end at the top deck of the cylinder block. A plurality of head bolt bosses in which the head bolts are threadably inserted are formed integrally in the jacket sidewall. Generally, in the conventional cylinder block, the jacket sidewall constitutes an external wall of the cylinder block, and thus, the top deck of the cylinder block has a two-layered flange structure consisting of a top end of the cylinder wall and a top end of the jacket sidewall.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved cylinder block for an internal combustion engine. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.